Radio communication systems are known to include a plurality of communication service providers that are accessed by a plurality of communication units requiring such communication services. In such a system, communication units (e.g., portable and mobile radios) typically require one or more communication services such as talkgroup calls, telephone interconnect, fax, high speed data, or low speed data. Further, advanced communication units are also capable of transmitting and receiving video and multimedia information over the air. In order to facilitate communications involving these types of resources, the communication unit must be able to access a service provider that is equipped with hardware (i.e. specialized equipment for each such resource) to complete the call.
There are several problems associated with the typical configuration described above. First, in order to meet all of a set of service requirements for a particular communication unit, the communication unit must find a service provider that can facilitate each of these types of communication. Assuming that there are some communication units that have extensive communications capabilities, and further assuming that these communication units roam throughout a large coverage area, this would require that each of the service providers within that coverage area be suitably equipped to handle all of these services. Such a configuration, particularly in high density areas requiring many service providers, is both cost prohibitive and resource inefficient. That is, because each of these communication services require expensive hardware, large scale redundancy results in system that is far too expensive to build and maintain. Further, while the radios roaming throughout the coverage area are capable of using these extensive resources, the lesser used of these resources remain idle for a high percentage of the time, thereby making for inefficient utilization.
A second problem with the foregoing configuration occurs after a particular service provider has been selected by a communication unit to provide communication services. As the communication unit roams throughout the coverage area, the signal quality or congestion of a particular service resource may degrade to an unacceptable level. Thus, the communication unit would need to re-affiliate with another service provider in order to establish a more reliable connection. This added step of having to re-affiliate can be quite problematic, particularly in areas where the signal quality and congestion are at or near threshold levels, resulting in undesired chatter.
When a communication unit cannot find a single service provider capable of supporting all of its service requirements, then the communication unit may still affiliate with a service provider that provides some portion of the set of service requirements. Thereafter, the communication unit has the supported services available to it, but is incapable of using the unsupported service requirements. That is, when the communication unit determines a need for one of these unsupported services, it must search for a suitable service provider to support this service requirement, potentially at the expense of losing support for other service requirements of that communication unit.
Accordingly, there exists a need for an improved method of providing communication services to roaming communication units that is not constrained by the shortcomings of the prior art. In particular, such a system that could economically and efficiently utilize the available communication service resources would be an improvement over the prior art .